射流射滴过渡的电弧光谱控制法的研究

Gas Metal Arc Welding(GMAW) is a welding process through droplet transfer. Study on the principle of metal transfer and its control are of great importance to the stability of the welding process, improvement of the weld formation and reducing of the spatter. The Pulsed MIG Welding(PMIG) has become a relatively widely used welding technology because of its controllability of spray transfer. The arc plasma contains much radiation spectral information about the droplet transfer in Gas Metal Arc Welding. The information of the arc spectrum, based on the thorough observation of the Pulsed MIG arc, was first used in its metal transfer control, truly realizing the welding process of One-Pulse-One-Droplet transferring. Thus, a new arc spectrum-controlled method of welding physical process was first founded in this research project.On the basis of the physical principle of the arc plasma spectrum, the physical essentials of the arc plasma can be actually reflected by the arc spectrum information. It can be realized through spectrum information technology(SIT) to refine the arc light and separate good quality spectrum signal, which can reflecting the process of the metal transferring. Compared with other present methods of arc sensing, the spectrum information technology has such advantages as plentiful information, high sensitivity, good selectivity, fast response speed, high spacial-time resolution and good performance of anti-disturbance.With the analysis of the radiation theory, energy transmission and the balance properties of the radiation spectrum of the arc plasma, the distribution characteristics of the arc spectrum along frequency, space, and time field was investigated, which provide theoretical foundation for the research on the spectrum information of Pulsed MIG welding with spray transfer. Pulsed MIG arc belongs to high voltage and heat plasma. Its radiation spectrum signal, which has the character of the Plank black radiation, is the addition of line spectrum, which is formed by exited radiation, on the background of the continuous spectrum, which was created by tenacious spectrum radiation and compound radiation. The relationship between line spectrum intensity and particle content and arc temperature have been summarized to be monotonous increasing and mono-hump distribution, which theoretically support the explanation to dynamic performance of line spectrum signal in Pulsed MIG arc..A special-used measuring system for the spectrum signal of the droplet transferring in Pulsed MIG welding, was set up in this research. Various metal transfer models in Pulsed MIG welding was analyzed from process experiments. Thus, the spectrum information about droplet transferring, such as One-Pulse-One-Droplet; One-Pulse-Two-Droplet transfer model, etc. was achieved; the spectral signal waveform models and their mathematical models for various transfer modes have been established; the relationship between the formation of waveform and the process of droplet transferring have been explained..There are two main monitoring methods developed in this research: one is based on spectral line detecting, in which One-Pulse-One-Droplet－Spectrum Later-peak Converting method was advanced; another is by special arc window spectrum intensity integral effect, in which a kind of the method is put forward about distinguish droplet transfer from slope of spectrum signal.Experiments on spectrum information automatic control for One-Pulse-One-Droplet spray transfer in Pulsed MIG Welding has been carried out thoroughly in spectrum control system, which was composed of spectrum line detecting system, microprocessor control system and inverting power source. The control rule was founded on the basis of experiment data, that is, keeping the average welding current or pulse unit energy(if pulse frequency is not changed) in certain technology range is very important to obtain One-Pulse-One-Droplet spray transfer.Based on the select principle of spectral window mentioned above, a special spectral window has been selected and the window

本研究提出利用电弧光谱信息控制气保护焊射流射滴过滤的原理，依据这一原理创立一种新的焊接控制法----射流射滴过渡的电弧光谱控制法及其装置。它是在原有知识创新研究（电弧光谱信息研究）的基础上提出的技术创新研究。此新方法有许多优点，有广阔的应用前景，属国内外首创，对促进焊接技术和电弧光谱信息技术的发展有重大理论和实际意义。